Compound needle

ABSTRACT

Two blades ( 14, 14 ) of a slider of a compound needle move back into blade grooves ( 8, 8 ) of a needle body ( 4 ) on the left and right side of a partition wall ( 9 ). An opening ( 18 ) is provided at the front ends of the blades ( 14, 14 ), and curved portions ( 19, 19 ) are provided on the backside of the front ends of the blades. Further, a thick section is provided at the front end of the partition wall ( 9 ), and a thin section is provided on the backside of the thick section. When the blades move forward from the blade grooves, the blades are centered at the thick section so that even if a lateral force is applied from a knitted loop to the blades, deformation of the blades is prevented by the contact of the two blades at the curved portions. In the blade grooves, the curved portions contact the thin section of the partition wall such that the force applied between the blades and the blade grooves does not increase.

TECHNICAL FIELD

The present invention relates to a compound needle used in a knittingmachine such as a flat knitting machine or a circular knitting machine.In particular, the present invention relates to a compound needleincluding a needle body having blade grooves, and a slider including twoblades that are movable back and forth in the blade grooves.

BACKGROUND ART

Patent Publication 1 (Japanese Patent No. 2,946,323) discloses acompound needle including a needle body having blade grooves, and aslider including two blades that are movable back and forth in the bladegrooves. At the front ends of the two blades of the slider, tongues areprovided. By the forward movement of the slider, the tongues close ahook at the front end of the needle body. By the further forwardmovement of the slider, the tongues move beyond the hook for looptransferring or the like. Further, the two blades are overlapped witheach other, and accommodated in longitudinal grooves provided in aslider jack. A butt of the slider jack is manipulated for moving theblades back and forth. The base end of the needle body is attached tothe needle jack, and the butt of the jack is used for manipulating theneedle body. Further, in order to prevent the undesirable movement ofthe slider by the movement of the needle body, one of the two blades hasan expansion at a position in the longitudinal groove of the sliderjack. The expansion contacts the side surface of the needle groove ofthe needle bed. By the frictional resistance, the undesirable movementof the slider is prevented.

Patent Publication 2 (WO 01/31102A1) discloses studies about the slidingresistance at the time of the forward movement of the tongues of thecompound needle beyond the hook of the needle body, and expansion of thespace between the blades when the blades are widened toward the left andright by the hook. Patent publication 2 proposes to provide a partitionwall between the blade grooves of the needle body, and dispose the twoblades on the left and right sides of the partition wall, respectively.As a result, when the tongues move forward beyond the hook, instead ofwidening the two blades at a large angle, the angle of widening theblades is reduced by the partition wall to reduce the size of expansiontoward the left and right. Further, since there is a gap correspondingto the partition wall between the blades, the sliding resistance betweenthe hook and the blades is small. Further, the partition wall functionsto guide the two blades, and scrub away the fiber debris entered betweenthe blades.

In the compound needle disclosed in Patent Publication 2, a gap isformed between the two blades projecting from the blade grooves. Whenthe blades hold a knitted loop, a force in a lateral (left or right)direction may be applied to the blades from the knitted loop. Forexample, when the blades hold the knitted loop at any of the oppositeends of the knitting fabric or when the blades hold the knitted loopwhich has been subjected to racking, since the knitted loop is pulled inthe lateral direction, the force is applied to the blades. As a result,the blades may be warped undesirably, and it may not be possible to holdthe hook between the two blades. Further, the two blades may be deviatedtoward one side of the hook undesirably. These problems may cause errorsin knitting.

TERMINOLOGY

In the description, “front/rear (forward/backward)” means the directionin parallel to needle grooves of needle beds. The forward movement meansthe movement toward the trick gap between the needle beds, and thebackward movement (retraction) simply means the movement away from thetrick gap between the needle beds. Further, the “left/right direction”means the direction which is parallel to the longitudinal direction ofthe needle beds, i.e., the direction to perpendicular to thelongitudinal direction (forward/backward direction) of the compoundneedle, and which is in parallel to the surface of the needle beds.Further, the front end means the end near the trick gap of therespective members. The base end means the end remote from the trickgap. The front side means the side near the trick gap, and the backsidemeans the side remote from the trick gap.

SUMMARY OF THE INVENTION Object of the Invention

An object of the present invention is to provide a compound needle inwhich left and right blades are centered relative to a hook by apartition wall, and it is possible to reliably hold the hook by theblades and comparatively reduce the friction of the blades in bladegrooves even if a force from a knitted loop is applied (claims 1 to 3).

Constructions of the Invention

According to the present invention, a compound needle comprises a needlebody having a hook and blade grooves with a partition wall. The hook isprovided at a front end of the composite needle, and a slider includes apair of blades. The blades are movable back and forth in the bladegrooves. The front ends of the two blades are opened toward the left andthe right, and the blades include curved portions curved inwardly on thebackside of the front ends of the blades, e.g., backwardly positionedfrom the front ends of the blades to some extent. Further, the partitionwall has the non-uniform thickness in the longitudinal directionincluding a relatively thick section on the front end side of the bladegrooves, and a relatively thin section, or a cutout section on thebackside of the thick section (Claim 1).

Preferably, the thickness of the partition wall is relatively thin onthe backside (Claim 2).

Further, preferably, when the two blades move back into the bladegrooves, the curved portions contact the thick section or the cutoutsection of the partition wall (Claim 3). Stated otherwise, when theblades move back into the blade grooves, it is preferable that thecurved portions contact the thin section or the cutout section of thepartition wall. At this time, the front ends of the blades may bepositioned at the thick section of the partition wall or may bepositioned at the cutout section of the partition wall. In theembodiment, the front ends of the blades are provided at the boundarybetween the thick section and the thin section. Since the two bladesmove almost together, in the specification, the “blades” may mean twoblades except the case in which one of the blades is describedparticularly.

Function and Advantages of the Invention

In the present invention, when the blades move forward from the bladegrooves, the blades are centered at the partition wall. Then, when alateral force from a knitted loop is applied to the blades, the curvedportions on the backside of the front ends of the blades, e.g.,backwardly positioned from the front ends of the blades to some extentcontact each other, and the force is received by the rigidity of the twoblades. Thus, it is possible to reliably hold the hook by the opening atthe front ends of the blades. When the blades move back into the bladegrooves, if the thickness of the partition wall is uniform, the curvedportions are expanded by the partition wall. Thus, the front ends of theblades are further expanded, and the friction of between the blades andthe blade grooves or the partition wall increases. In contrast, in thepresent invention, the curved portions of the blades contact the thinsection or the cutout section of the partition wall. Thus, by providingthe curved portions of the blades, it is possible to reduce the increasein the friction between the partition wall or the blade grooves and theblades (claims 1 to 3).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 includes a plan view and a side view showing main components of acompound needle according to an embodiment of the present invention, asviewed from two directions.

FIG. 2 includes cross sectional views showing cross sections of thecompound needle in FIG. 1 at four positions (a) to (d).

FIG. 3 is a plan view showing main components of the compound needle inFIG. 1.

FIG. 4 is a plan view showing the main components of the compound needlein FIG. 1 in a state in which blades starts to move forward from bladegrooves toward a hook.

FIG. 5 is a plan view showing the compound needle in FIG. 1 in a statein which the blades further move forward beyond the hook.

EMBODIMENTS

An embodiment will be described with reference to FIGS. 1 to 5. In thedrawings, a reference numeral 2 denotes a compound needle, and areference numeral 4 denotes a needle body. A hook 6 is provided at thefront end of the needle body 4. The portion of the needle body 4 on thebackside of the hook 6 may be referred to as a needle stem or a shank.Reference numerals 8, 8 denote a pair of blade grooves provided in theneedle stem. The blade grooves 8 are separated into the left side andthe right side by a central partition wall 9. The right side and theleft side of the blade grooves 8, and the partition wall 9 aresymmetrical with each other about the central line of the needle body 4in the longitudinal direction. In a plan view of FIG. 1, guides 25 asdescribed later are cut away.

The partition wall 9 includes a thick section 10 at the front end, and athin section 11 in the central position of the partition wall 9, on thebackside of the thick section 10, and a thick section 10 b in therearmost position of the partition wall 9. The thick section 10 b maynot be provided in the rearmost position. In this case, the thin section11 may be provided also in the rearmost position. Borderlines 13 betweenthe thick section 10 and the thin section 11, and between the thinsection 11 and the thick section 10 b, and the bottom 12 of the bladegrooves 8 are shown by broken lines in a side view of FIG. 1. Theborderline 13 between the thick section 10 on the front end side and thethin section 111 on the backside of the thick section 10 extendsobliquely from a lower rear position to an upper front position of theblade grooves 8. Thus, at the position (c) of the cross section, thethickness of the partition wall 9 in the upper position is differentfrom the thickness of the partition wall in the lower position of theblade grooves 8, i.e., the thickness is large on the bottom side, andthe thickness is small on the upper side. Instead of providing theborder between the thick section 10 and the thin section 11 obliquelylike the borderline 13, the partition wall may have the uniformthickness in the upper position and the lower position of the bladegrooves 8, and the thickness of the partition wall may be changed in theforward/backward direction by tapering the partition wall from the thicksection 10 to the thin section 11. The thickness of the partition wallmay be changed stepwise in the forward/backward direction between thethick section and the thin section.

Reference numerals 14, 14 denote a pair of blades. As shown in the sideview of FIG. 1, the blades 14, 14 and a slider body 26 on the backsideof the blades 14, 14 jointly make up a slider of the compound needle 2.FIG. 1 shows a state in which the blades 14, 14 are retracted (moveback) into the blade grooves 8, 8. On the backside of the needle body 4,a body jack (not shown) is provided. The slider body 26 or the body jackis manipulated by a butt (not shown), e.g., using a cam of a carriage.At the front ends of the blades tongues 16 are provided. The bottom 17of the blade 14 is shown by a broken line in the side view of FIG. 1.The front ends of the blades 14, 14 are slightly opened to the left andright sides to form an opening 18 as shown in FIGS. 4 and 5. On thebackside of the opening 18, the blades 14, 14 have curved portions 19,19. The curved portions 19, 19 of the blades 14, 14 are curvedelastically to contact each other. However, it is not necessary that thecurved portions 19 of the blades 14, 14 contact each other. For example,a small gap may be present between the blades 14, 14 at the curvedportions 19 as long as the gap between the blades 14, 14 at the curvedportions 19 is smaller than the gap between the blades 14, 14 at theother portions.

The blades 14, 14 contact each other at the curved portions 19, and thegap between the blades 14, 14 on the upper backside of the curvedportions 19 is expanded to form expanded portions 22. Since the blades14, 14 contact each other at the curved portions 19 or since the gapbetween the blades 14, 14 is the minimum at the curved portions 19, thesliding resistance between the blade 14 and the partition wall 9 or theblade grooves 8 is the maximum at the positions of the curved portions19. As shown in the side view of FIG. 1, by a guide surface 24 providedat the lower surfaces of the guides 25, the expanded sections 22 areguided such that the blade 14 sinks in the blade grooves 8 when theblade 14 is retracted.

FIG. 2(a) to FIG. 2(d) are enlarged views showing cross sections of theneedle body 4 at the positions (a) to (d) in FIG. 1. The depth of theblade grooves 8 gets larger from the thick section 10 at the front endof the partition wall to the thin section 11. At the positions (a), (b),the partition wall is thick. At the position (c), the upper portion ofthe partition wall is thin, and the lower portion of the partition wallis thick. At the position (d), the partition wall is thin from the upperportion to the bottom portion. When the blades 14, 14 are retracted tothe position (c) in the blade grooves 8, 8, the front end of the blade14 near the opening 18 contacts the thick section 10, and the curvedportion 19 of the blade 14 on the backside contacts the thin section 11.

FIG. 3 shows one single blade 14. FIG. 4 shows a state in which theblades 14, 14 move forward from the blade grooves 8 to a position justbefore the hook 6. The front ends of the blades 14, 14 are openedoutwardly to both of the left and right sides to form the opening 18.The tongues 16 are provided on the front side of the expanded sections22 in the rear position. The tip of the hook 6 is closed using thetongues 16. Further, the tongues 16 are used to keep the loop for looptransferring or knocking over. The tongue 16 includes the curved portion19 on the backside of the opening 18. The curved portion 19 is curvedinwardly beyond an inner line in the longitudinal direction of the blade14 indicated by a dotted line in FIG. 3. The pair of the blades 14, 14elastically contact each other at the curved portions 19, 19. It is notabsolutely necessary that the blades 14, 14 contact each other at thecurved portions 19, 19. Since the blade 14 contacts each other at thecurved portion 19, or the gap between the blade 14 is small at thecurved portion 19, the sliding resistance with the partition wall 9 isconcentrated at the curved portion 19.

Operation of the embodiment will be described. As shown in FIG. 1, whenthe blades 14, 14 are retracted into the blade grooves 8, 8, portions ofthe tongues 16 are hidden in the blade grooves 8, 8, and are notexposed. At this time, the curved portion 19 is positioned at the thinsection 11 of the partition wall 9. Thus, the partition wall does notwiden the gap between the curved portions 19, 19, and the force appliedbetween the partition wall and the curved portion 19 is small. Further,since the curved portion 19 contacts the thin section 11, the expansionbetween the blades 14, 14 at the opening 18 is reduced, and the forceapplied between the curved portions 19, 19 and the left and right outerside walls of the blade grooves 8, 8 is small. Thus, the blades 14, 14are, so called in the relaxed state, and are accommodated in the bladegrooves 8, 8.

As shown in FIG. 4, when the blades 14, 14 move forward to the hook 6 toclose the tip of the hook 6 by the tongues 16, 16, a problem may occurdepending on the position and orientation of the blades 14, 14 relativeto the hook 6. In order to ensure that the blades 14, 14 are suitablypositioned or oriented relative to the hook 6, centering of the blades14, 14 in the blade grooves 8, 8 is necessary when the blades 14, 14move forward. Further, it is necessary to prevent the change in theorientation of the blades 14, 14 due to the lateral force applied fromthe knitted loop held by the tongues 16, 16. Thus, the blades 14, 14move forward from the blade grooves 8, 8 while the blades 14, 14 arecentered at the thick section 10.

Next, when the tongues 16 hold the knitted loop by knocking over of theprevious loop or the like, the force in the lateral direction(left/right direction) applied from the knitted loop may cause aproblem. For example, if the knitted loop is positioned at the right endor the left end of the knitting fabric, or if the knitted loop has beensubjected to racking, a tensioning force in the left or right directionis applied to the knitted loop. If the force is received by only oneblade 14, the blade 14 may warp, and the two blades are deviated towardone side, i.e., the left or the right side. As a result, it may becomeimpossible to hold the hook 6 in the opening 18. However, in theembodiment, since the blades 14, 14 contact each other at the curvedportions 19, 19, the overall rigidity of the blades 14, 14 is twice aslarge as the rigidity of the single blade. Therefore, it is possible toprevent warpage of the blade by the tension of the thread, and reliablyhold the hook 6. Even if there is a small gap initially between thecurved portions 19, 19, if one of the blades that firstly receives thetensioning force of the thread is deformed to close the gap, the curvedportions 19, 19 contact each other to prevent further deformation. FIG.5 shows a state in which the blades 14, 14 move forward further untilthe tongues 16 move to a position beyond the hook 6.

As described above, in the embodiment, the blades 14, 14 are centered atthe thick section 10 of the partition wall 9. Further, even if the forcefrom the knitted loop is applied to the blades 14, 14, since the twoblades 14, 14 contact each other at the curved portions 19, 19,deformation such as the warpage of the blades is minimized. As a result,it is possible to reliably hold the hook 6 at the opening 18. Thus, theblades 14, 14 do not impinge upon the hook 6, and are not deviatedtoward one side of the hook 6.

Entry of the dust such as fabric debris into the blade grooves 8 isstudied. When the tongues 16, 16 contact a thread or the like, fabricdebris or the like may be sandwiched between the tongues, and broughtinto the blade grooves 8, 8. Thus, the sliding friction between theblades and the blade grooves is increased. Therefore, cleaning operationfor removing the fabric debris is required. In the cleaning process, forexample, the blades move forward, and a compressed air is blown to theopening 18. In the embodiment, the dust such as the fabric debris isscrubbed down by the thick section 10. At the thin section 11, since thewidth of the blade grooves 8 is larger than the thickness of the blades,the blades 14, 14 can move forward, and move back until the gap isclogged with the fabric debris. Thus, the cleaning operation of thecompound needle does not have to be performed frequently.

In the embodiment, the partition wall includes the thin section 11.Alternatively, instead of providing the thin section 11, a cutoutsection may be provided. The thin section 11 is provided for reliablyguiding the blades.

If the hook 6 is tapered from the base portion to the head portion(front end of the hook 6) such that the thickness of the hook 6 isgradually decreased, by specially designing the shape of the blades 14,14 at the tongues 16, the sliding resistance between the hook 6 and thetongues 16 is reduced. In the modified embodiment, the shape of theblades 14, 14 is changed, e.g., at the portions of the tongues 16, 16,in particular, the portions of the tongues 16, 16 on the backside of thecurved portions 19, 19. In the portions, lower portions of the blades14, 14 are curved outwardly toward both sides (left and right sides) ortwisted outwardly to gradually increase the gap between the blades 14,14 from the upper portion to the lower portion (bottom portion). As aresult, for example, upper portions of the blades 14, 14 contact eachother at the curved portions 19, 19, and a gap is formed between thelower portions of the blades 14, 14. The gap matches the tapered portionof the hook 6 to decrease the sliding resistance. The distance betweenthe blades is increased at the lower portion of the curved portion 19 toreduce the sliding resistance with the tapered hook. This effect is alsoadvantageous in the case where no partition wall 9 is provided betweenthe blade grooves.

1. A compound needle comprising: a needle body having a hook and bladegrooves with a partition wall between them, the hook being provided at afront end of the needle body; and a slider including a pair of blades,the blades being movable back and forth in the blade grooves, whereinfront ends of the two blades are opened toward left and right, and theblades include curved portions curved inwardly on a backside of thefront ends of the blades, and wherein the partition wall has anon-uniform thickness in a longitudinal direction including: arelatively thick section on a front end side of the blade grooves; and arelatively thin section or a cutout section on a backside of the thicksection.
 2. A compound needle according to claim 1, wherein thethickness of the partition wall is relatively thin on the backside.
 3. Acompound needle according to claim 1, wherein when the two blades moveback into the blade grooves, the curved portions contact the thicksection or the cutout section of the partition wall.